Estuarine and open coastal biotopes along the Chennai coast were sampled bimonthly for total heterotrophic as well as phosphate solubilizing bacteria (PSB) between January and December 1999. THB was high during months January, September and November. THB population ranged from 6.03 – 8.13 x 105 cells ml-1 and phosphate solubilizing bacterial population from 1.00–1.3 x 103 cells ml-1. Pseudomonas and Bacillus were found to solubilize more phosphates than others. Further the phosphate solubilizing potential of Pseudomonas was confirmed in broth cultures where P solubilization was1700 mg /ml-1 associated with reduction of pH.